Molded egg carton



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MOLDED EGG CARTON Filed Aug. 6, 1964 3 Sheets-Sheet l INVENTOR. ALFREDE. ComsTocx Ju 9, 1965 A. E- COMSTOCK MOLDED EGG CARTON 3 Sheets-Sheet 2Filed Aug. 6, 1964 INVENTOR ALFRED E.

CoMs TOCK ne 29, 1 5 QA.VE. COMSTOCK 3,191,844

MOLDED EGG CARTON Filed Aug- 6, 1964 v 3 Sheets-Sheet 3 INVENTOR. f:ComsrocK United States Patent $91,844 MOLDED EGG CARTON Alfred E.Cornstoclr, 9 Los Cerros Drive, Greenbrae, Calif. Filed Aug. 6, 1964,Ser. No. 387,660 6 Claims. (Cl. 229-25) This invention relates to animproved integrally molded cellular egg carton, and more particularly itrelates to a so-called two-by-six style carton in which the cells arearranged in two rows of six each. This application is acontinuation-in-part of my copending application Serial No. 277,906,filed on May 3, 1963, now abandoned.

One important object of the present invention is to provide an improvedmolded egg carton that has unusual strength characteristics,particularly for resisting the downward crushing or compression force onthe carton that so often occurs during shipment and storage. Myinvention has solved this strength problem by a unique arrangement ofhingedly articulated sections including a cellular bottom section and apair of non-cellular top sections attached at opposite sides of thebottom section. Within the cellular bottom section are a series ofspaced apart and uniquely shaped upstanding portions which cooperatewith the top sections when the carton is closed to make it unusuallyrigid and strong and thus capable of withstanding severe loads,particularly along its longitudinal center line, as well as its sidesand ends.

Another object of my invention is to provide a molded egg carton whosebottom and cover sections are originally formed with sloped side wallsso that the open cartons will readily nest together with other likecartons, and a further object is to provide a carton wherein the slopedwalls of each cover section are automatically flexed or deformedslightly from their originally molded shape and are forced closertogether into a substantially non-sloped, vertical position when thecarton is closed. This flexing or deformation of the cover side wallsthat occurs as the covers are closed results in an increased amount ofspace within each cell of the carton. Thus, even the largest sized eggscan be accommodated without any portion of the cover sections engagingand possibly damaging them. Also, when the two cover sections arerotated and closed, they are held tightly in a firm frictional lockingengagement with each other within a series of aligned slots in theupstanding portions between the rows of egg cells. This unique closureretains the cover sections firmly in position during handling andshipment, but at i the same time provides the user with easy access tothe product within. Moreover, when the engaged side walls of the twocover sections are pressed tightly together within the slots and theengaged side walls assume a substantially upright position, thecompression strength of the carton is thereby increased.

Another feature of my improved carton is that when stacked and nestedwith other such cartons before being filled, the cartons will not wedgeor jam together. Also, with large stacks of cartons there will be noslumping or irregularity in the level of any of the cartons, and allcartons in the stack, including the uppermost one, will naturallymaintain a level position. This can be a particularly important factorwhen the cartons are used in large numbers for machine filling andpackaging. In my invention these stacking problems have been solvedwithout the need for the horizontal stacking flange heretofore providedalong the outer edges of cover sections on prior art cartons.

Still another object of my invention is to provide an improved moldedpulp egg carton having a unique configuration that presents aparticularly clean and attractive package. The cover sections, whenmoved to the closed position and held closely together, form a planesmooth top on the carton that is free from indentations and is thereforereadily usable for various printing designs.

Yet another important object of my invention is to provide an egg cartonthat can be molded from relatively simple molding apparatus usingconventional molding procedures.

While fibrous pulp material is most commonly used in making molded eggcartons, my carton may also be readily manufactured from any suitablethermoplastic sheeting material. The latter material has certainadvantages because of its light weight and transparency which canenhance the display of the cartons. The use of this relatively thinthermoplastic material is made possible because of the remarkablestrength characteristics afforded by the unique structural features ofmy carton.

A further object of the present invention is to provide an egg cartonthat can be loaded and closed with particular ease and efficiency athigh production rates by automatic egg loading apparatus.

Other objects, advantages and features of my invention will becomereadily apparent from the following detailed description of oneembodiment thereof presented with reference to the accompanyingdrawings, in which:

FIG. 1 is a view in perspective of a two-by-six egg carton embodying theprinciples of the invention;

FIG. 2 is a plan view of the egg carton shown in FIG. 1 with both coversections open;

FIG. 3 is a view in end elevation of the carton shown in FIG. 2;

FIG. 4 is a view in end elevation with portions in section showing thecover sections of the carton in FIGS. 1 to 3 as they are being closed;

FIG. 5 is a view in end elevation showing the carton of FIG. 4 with itscover sections almost fully closed;

FIG. 6 is a view in end elevation and in section showing the carton ofFIGS. 4 and 5 with its cover sections fully closed;

FIG. 7 is a fragmentary plan view showing the carton of FIG. 6 with thecover sections fully closed;

FIG. 8 is a view in elevation and in section taken along line 88 of FIG.7;

FIG. 9 is an enlarged fragmentary end view in elevation showing detailsof the cover section for cartons embodying the principles of theinvention.

Referring to the drawings, FIG. 1 shows a view in perspective and FIG. 2shows a plan view of an integrally molded pulp carton 10 embodying theprinciples of the invention. Essentially, it comprises a cellular bottomsectionll having opposite sides 12 to which are connected a pair ofcover sections 13. The bottom or tray section 11 is partitioned into twolongitudinal rows of egg-receiving compartments or cells 14, each ofwhich is tapered downwardly and has an embossed bottom portion 15 forcushioning an egg contained therein. The cells 14 may utilize anysuitable geometric configuration which provides the generally taperedshape adaptable to receive an egg. The particular shape of the cells 14shown in the drawings is illustrative only and is not meant to limit thescope of the invention. Integral with the bottom section 11 of thecarton 10 and spaced apart along its longitudinal center line are anumber of hollow upstanding members 16 which are generallyfrusto-conical in shape and open at their upper end. These lattermembers 16 extend well above the level of the bottom section 11 and areunique elements of my carton both in structure and in function.Essentially, the egg receiving cells 14 are formed by the combination ofthe lower portions of the upstanding members 16, by a-series oflongitudinal partition elements 17 connecting adjacent upstandingmembers 16, and by transverse partition elements 18 conarouses nectingthe upstanding members 16 and the opposite side walls 1.2 of the bottomsection 11. Around the upper edges of the cells 14 at the ends of thebottom portion 15 and along the side walls 12 is a horizontal flange orrim portion 19.

The tapered upstanding members 16 extend well above the surrounding rimof the cells 14 and all are provided with a diametrical slot acrosstheir upper open end which extends downward to a point substantially inthe same plane as the upper rim 19 of the bottom section 11. These slots20 through the upstanding members 15 are aligned with themselves andwith the longitudinal partition elements 17 along the longitudinalcenter line of the bottom section 11. At the upper end of each tubularpost member 16, the slot 20 flares open to form upwardly divergentcurved edges 21 that cooperate with the cover sections 13 when they arearticulated in closing the carton, as described below. However, neartheir lower ends the slots 20 narrow to a uniform width that isapproximately twice the wall thickness of the cover sections 13.

Each cover section 13 is connected integrally with a side wall 12 of thebottom section 11 by a longitudinal hinge joint 22 that is formed as ascore line in the conventional manner during the molding of the pulpcarton 19. The cover sections 13 may be identical in size and shape,each being substantially tub shaped and having a rectangular planar top23 connected to opposite inboard and outboard side walls 24- and 25,respectively. The latter are joined together by end walls 26 that are atleast partially curved to form rounded corners on the cover sections. Avery narrow integral flange or rim portion 2'7 is preferably providedaround the upper edges of both cover sections. The side walls 24, 25 andthe end walls 26 of the cover sections 13 are outwardly inclined whenthe carton is molded as are the side walls 12 of the bottom section 11.This sloping of all side walls enables the carton to be easily strippedfrom a mold as it is made. Moreover, it enables the cartons to be nestedtogether and conveniently stacked in large quantities for shipment orstorage or for use in automatic loading devices.

The carton 10 is preferably made from conventional paper pulp materialscommonly used for egg cartons and the like, although other suitablemoldable materials may possible be utilized. When formed, the carton 16is molded as a single unit with the cover sections 13 in their extendedopen position. The rim 27 extending from the upper edges of the sidewalls 24 and 25 and from the end walls 26 is in the same plane as therim portion 19 at the upper edge of the cells 14 on the bottom section11. This is an important feature of my invention because it enables themolds for my carton to utilize a simple single plane molding strap. Suchmolds are relatively inexpensive and easier to operate and service thanmolding apparatus heretofore used for cartons having complicatedconfigurations that require multiple plane molding straps. A majoradvantage of my carton is that its unique but relatively simpleconfiguration makes possible the utilization of automated apparatus andmethods for efficient, high speed production.

In the present invention particular advantages are derived from the factthat the cover sections 13 are caused to flex and thereby change theirshape a significant amount as they are closed after the carton has beenloaded. This flexing is due in part to the construction and shape of thecover sections as originally formed and to a new cooperation betweenthem and the upstanding members 16 in the bottom section of the box.This feature of the invention will now be described in greater detailwith reference to FIGS. 4 to 7. These figures illustrate how the coversections of a carton 19 change their shape as they are closed byautomatic closing apparatus on a carton-loading production line. Thecomplete closing apparatus is not shown since it forms no part of thepresent invention. However, a closure plate 29 which is part of such amechanical closing apparatus is shown in the position where it wouldnormally be oriented, that is vertically above the carton, partiallywithin the slots 20 and aligned with the longitudinal axis of thecarton. Assuming that a carton has been denested mechanically from asupply stack of cartons and the carton cells have been loaded with eggs,a force would be applied by the automatic closing apparatus to the coversections to rotate both of them simultaneously about their scoredlongitudinal hinge lines 22. When the cover sections 13 are rotated tothe position shown in FIG. 4, the outer sloped wall 25 of each covermember 13 engages the closure plate 29. Now, as the cover sections arerotated further, these outer walls 25 press against the closure plate 29and flex from their original sloped shape toward a substantiallyvertical position with respect to the planar top 23 of the coversection. When the cover walls 25 approach the lower end of the slots 29in the members 16 they slide off the closure plate 29 and push againsteach other as they are forced the rest of the way into the slots. Sincethe width of the slots 20 near their lower ends and for a substantialdistance above the side walls of the bottom section is approximatelytwice the thickness of the cover walls 25, as stated previously, theseslots provide opposed surfaces that serve to grip the cover sectionsfirmly when they are closed. Thus, when completely closed the coversections are frictionally engaged and locked in place and are now in anupright or substantially vertical position (FIG. 6).

During the flexing of the outer walls 25 of the cover sections 13 asjust described, the inner walls 24 also may flex toward the verticalposition. The amount that the inner walls will flex from theiroriginally molded sloped shape depends on the width of the cover sectionplanar top 23 indicated typically by the dimension A in FIG. 6. Forexample, if the dimension A was increased from that shown, the inboardwalls 2d would come closer to being vertical when the cover sections 13are closed due to the fact that the outer walls 25 of both coversections are in abutment and would force the inboard wall members 24 toflex outwardly. As shown in FIG. 6, the full flexing of the outboardside walls 25 and even partial flexing of the inboard side walls 24increases the amount of space available within the carton. Thus, eventhe larger sized eggs can be accommodated without the cover wallstouching them and possibly causing breakage during shipment or handlingof the cartons. However, if needed, even more egg space can be providedby increasing the dimension A. When the width of its planar top member23 on each cover section (the dimension A) is substantially equal to thedistance between the hinge joints 22 and the longitudinal center line ofthe carton 10 which extends midway through the slots 20 of all theupstanding members 16, both walls 24 and 25 will become vertical whenthe box is closed and maximum egg space is provided.

As stated above, when the inner and outer walls of the cover sectionsflex and are pushed together, the end walls 26 simultaneously bulgeoutwardly in a longitudinal direction. To accommodate this compensatinglongitudinal distortion in the cover sections, the carton is initiallyformed, as shown in FIG. 2, with the cover sections 13 somewhat shorterthan the bottom section 11 by an amount designated typically by theletter B. Now, when the cover sections are closed, as shown in FIG. 7,their end walls 26 bulge out just enough due to the flexing of theoriginally sloped side walls 24 and 25 so that the cover rim portions 27become even with and substantially match the rim portion 1.9 of thebottom section 11 of the carton.

While I have described the carton 10 as being easily closable byautomatic production line machinery, it can of course, be readily closedby hand or by other means wherein one cover section is closed firstbefore the other cover section. In this latter instance no closure plateis required and the upper curved edges 21 of the slots 20 in the postmembers 16 function to help cam the first cover section into position.As this first cover section is rotated, its outer wall initially engagesthe opposite curved edges 21 of the center post slots 2t), and as it iscammed downward to the bottom of the slots, its outer wall flexes fromthe sloped to the vertical position relative to the planar top portion23. Now, when the other cover section is closed, its outer wall strikesthe first cover section already in place and is cammed downwardly into atight locking engagement with the other cover section at the lower endof the slots.

As stated previously, it is important that egg cartons be formed so thata large number of them can be conveniently nested together in largestacks for shipment and storage, and for use in automatic loadingapparatus. Yet, when stacked in this manner it is necessary that thecartons do not tend to wedge or stick together, since they must bereadily separable for feeding and handling by the egg loading machines.The carton it of the present invention fulfills both of theserequirements. To facilitate nesting, the side walls 24 and 25 of thecover sections 13 when formed are sloped inwardly as previouslydescribed at a predetermined angle (e.g., approximately 12 degrees),

and the cells 14 and the upstanding post members 16 of the bottomsection 11 are also similarly tapered to facilitate the nesting of thecartons. To assure that the cartons 10 can be de-nested easily, theoutboard side wall of each cover section 13 has a particularly uniqueconstruction along its longitudinal junction with the planar top 23. Asshown in FIG. 9, the outside edge of the junction 30 is relatively sharpand is substantially a right angle, although just above the junction 30of an open carton the side wall 25 slopes outwardly at the normal slopeangle (e.g., 12 degrees). The inside of each cover section 13 has asmoothly curved fillet 32 between the side wall 25 and the planar top23. Thus, due to the edge 31, as shown in FIG. 9, a small amount ofspace 33 is maintained between the outer Walls of adjacent coversections, and the cartons when stacked will not wedge tightly together,but will remain readily separable. Another function of the sharp outsideedge 31 of each cover section is that it causes the open cartons tostack in a level position rather than slumping together despite thenumber of cartons in the stack.

From the foregoing it will be apparent that I have provided an improvedmolded egg carton that has unusual structural strength and eggprotection features, as well as a clean, attractive appearance. Theunique arrangement of its various structural elements, including theslotted upstanding members 16, enables the carton to be manufactured atrelatively low cost using conventional molding procedures and alsohighly adaptable for use with automated egg handling machines.

To those skilled in the art to which this invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest themselves without departingfrom the spirit and scope of the invention. The disclosures and thedescription herein are purely illustrative and are not intended to e inany sense limiting.

I claim:

1. A molded two-by-six egg carton including:

a bottom section having egg supporting means, side and end Wall means,and longitudinal and transverse partition means all cooperating togetherto form two rows of six egg receiving pockets;

a pair of generally tub shaped cover sections having outboard side wallsand inboard side walls integrally connected to the opposite side wallmeans of said bottom section and curved end walls at opposite ends ofeach cover section between its side walls, said cover section side wallsof an open carton being sloped outwardly when the carton is formed inthe open position so that the distance between the outer edges of eachcover side wall is greater than one half of the overall width ofsaidbottom section; I

a plurality of integrally upstanding gripping members located at spacedapart intervals on said bottom section and extending above the upperedges of the bottom section, said upstanding members being transverselyslotted above the side walls of said bottom section and along thelongitudinal center line thereof, each slot being substantially uniformin width at its lower end and diverging upwardly to form a relativelywide opening at its upper end;

said slots being adapted to receive the outboard sloped side walls ofsaid cover sections, to flex them toward a substantially verticalposition and thereby to retain them in frictional engagement when thecarton is closed.

2. The carton as described in claim 1 wherein said cover sections areslightly shorter in length than said bottom section when the carton isformed in the open position, said cover sections tending to increase inlength to match generally the shape of the bottom section when the endwalls of the cover sections push outwardly as their side walls arepushed together when the carton is closed.

3. A molded egg carton comprising:

a bottom section having egg supporting means, side and end wall means,and longitudinal and transverse partition means all-cooperating togetherto form two rows of six egg receiving pockets;

a pair of tub shaped cover sections having outboard side walls andinboard wall sides hingedly connected to opposite side walls of saidbottom section the distance between the longitudinal edges of the sidewalls of each cover section being greater than one half the width ofsaid bottom section;

a plurality of upstanding members extending upwardly above the upperlevel of said bottom section at the junction of said longitudinal andtransverse means, and spaced apart along the longitudinal center line ofsaid bottom section, said upstanding members having transverse slotsopen at their upper ends and aligned along the longitudinal center lineof said bottom section, each said slot being relatively narrow at itslower.

end and providing opposed gripping surfaces and diverging upwardly andoutwardly at its upper end to provide cumming surfaces, said slotsreceiving said outboard side walls of each said cover section andthereby retaining them in frictional engagement when the carton isclosed.

4. A molded egg carton comprising:

a bottom section having egg supporting means, side and end wall means,and longitudinal and transverse partition means all cooperating togetherto form two rows of six egg receiving pockets;

a pair of tub shaped cover sections having outboard side walls andinboard side walls hingedly connected to opposite side walls of saidbottom section, said side walls being sloped when the carton is moldedin the fully open position, with the distance between the longitudinaledges of the side walls of each cover section being greater than onehalf the width of said bottom section;

a plurality of tapered upstanding members extending upwardly above theupper lever of said bottom section at the junctions of said longitudinaland transverse means, and spaced apart along the longitudinal centerline of said bottom section, said upstanding members having transverseslots open at their upper ends and aligned along the longitudinal centerline of said bottom section, said slots forming upwardly divergent edgeson each said upstanding member adapted to receive said outboard sidewalls of said cover sections and to cause them to flex toward asubstantially upright position while retaining them in frictionalengagement when the carton is closed.

5. A molded egg carton comprising:

a bottom section having egg supporting means, side and end wall means,and longitudinal and transverse partition means all cooperating togetherto form two rows of six egg receiving pockets;

a pair of tub shaped cover sections each having sloped outboard andinboard side Walls flexibly attached to a planar top portion with saidoutboard side Walls being integrally hingedly connected alonglongitudinal hinge lines to opposite side walls of said bottom section,the distance between the longitudinal edges of the side Walls of eachcover section when the carton is molded being greater than one half thewidth of said bottom section, each said outboard side wall having arelatively sharp angular edge along the outside longitudinal junctionwith its planar top portion, and a corresponding concave surfaceextending along the inside of said longitudinal junction within eachcover section;

a plurality of tapered upstanding members extending upwardly above theupper level of said bottom section at the junctions of said longitudinaland transverse means, and spaced apart along the longitudinal centerline of said bottom section, each said upstanding member having atransverse slot open at its upper end and aligned along the longitudinalcenter line of said bottom section, said slots being adapted to receivesaid outboard side walls of each said cover section and to retain themin frictional engagement When the carton is closed, said sharp outsideedges thereby being brought together to form a substantially smoothsurface on the top of the closed carton.

6. An egg carton comprising an elongated tray provided With parallelrows of pockets and having end edges and longitudinal edges adjacentsaid pockets,

a cover section hingedly connected to each longitudinal edge of saidtray, each cover section being generally tub shaped and having a bottomwith connected end Walls and side Walls diverging outwardly therefromand terminating in connected end edges and longitudinal edges, thedistance between the longitudinal edges of each cover section beinggreater than one half the Width of the tray,

and cover gripping means integral with the tray and extending above andbetween the pockets thereof for gripping and retaining the coversections in position over the pockets.

References Cited by the Examiner UNITED STATES PATENTS 2,404,704 7/46Guyer 229-44 X 2,591,471 4/52 Schwertfeger 229-45 2,634,039 4/53Schwertfeger 22944 X 2,738,914 3/56 Hatch 2292.5 3,028,065 4/62 Reifers22945 X 25 FRANKLIN T. GARRETT, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Non3,191,844 June 29, 196

Alfred E Comstock It is hereby certified that error appears in the abovenumbered petent requiring correction and that the said Letters Patentshould read as corrected below.

Column 3, line 45, for "possible" read possibly column 5, line 29, after"edge" insert 31 column 6, line 10, strike out "to"; line 59, for"lever" read level Signed and sealed this 28th day of December 1965.

(SEAL) Attest:

ERNESFVRSVHDER EDVUUUII.BRENNER Attesting Officer Commissioner ofPatents

1. A MOLDED TWO-BY-SIX EGG CARTON INCLUDING: A BOTTOM SECTION HAVING EGGSUPPORTING MEANS, SIDE AND END WALL MEANS, AND LONGITUDINAL ANDTRANSVERSE PARTITION MEANS ALL COOPERATING TOGETHER TO FORM TWO ROWS OFSIX EGG RECEIVING POCKETS; A PAIR OF GENERALLY TUB SHAPED COVER SECTIONSHAVING OUTBOARD SIDE WALLS AND INBOARD SIDE WALLS INTEGRALLY CONNECTEDTO THE OPPOSITE SIDE WALL MEANS OF SAID BOTTOM SECTION AND CURVED ENDWALLS AT OPPOSITE ENDS OF EACH COVER SECTION BETWEEN ITS SIDE WALLS,SAID COVER SECTION SIDE WALLS OF AN OPEN CARTON BEING SLOPED OUTWARDLYWHEN THE CARTON IS FORMED IN THE OPEN POSITION SO THAT THE DISTANCEBETWEEN THE OUTER EDGES OF EACH COVER SIDE WALL IS GREATER THAN ONE HALFOF THE OVERALL WIDTH OF SAID BOTTOM SECTION; A PLURALITY OF INTEGRALLYUPSTANDING GRIPPING MEMBERS LOCATED AT SPACED APART INTERVALS ON SAIDBOTTOM SECTION AND EXTENDING ABOVE THE UPPER EDGES OF THE BOTTOMSECTION, SAID UPSTANDING MEMBERS BEING TRANSVERSELY SLOTTED ABOVE THESIDE WALLS OF SAID BOTTOM